When looking at issues, either by going through the issues tab or the code tab, the box that shows an issue shows much useful info, including the line number of the code, but not the rule’s key. One has to click on the “Why is this an issue?” link to get the popup that gives the key.
Sometimes it’s hard to tell exactly which rule is being violated since the text in the box isn’t always the base name of the rule, but is adapted to the specific code. If one is familiar with some of the key names then one could see right away which rule it is.
There seems to be space available in the box, but if not, the phrase “Why is this an issue?” could be replaced with simply “Why?” (still more clear than the ellipses in older versions).